instantsearch.js: CSS is not included in production

[imphil]

The CSS coming from the instantsearch.js bundle is included in search.js:

import 'instantsearch.js/dist/instantsearch.css'

That works fine in development builds (yarn dev), but doesn't work in production build (yarn build). In these builds, the CSS is simply not built.

It turns out that the ./node_modules/instantsearch.js/package.json specifies sideeffects: false, where it should actually specify

"sideEffects": [
  "*.css"
],

(Thanks to fkhadra/react-toastify#334 (comment) for the hint.)

Newer instantsearch.js versions (>= 3) use a different structure, so let's see if upgrading to a new version fixes things, otherwise we need to go with an upstream bug. For now, a workaround is sufficient.